CN100501460C - Composite triangular pyramid type cube-corner retroreflection sheet and retroreflection object - Google Patents

Abstract

A composite cube-corner retroreflection element comprising at least two groups of sub retroreflection elements which are divided by three side surfaces mutually crossing at almost right angles by means of 3-directional V-shaped parallel groove groups that mutually cross and have substantially symmetrical sections, and which are disposed in the most densely filled state so as to project toward one side on a common sub plane (SH-SH'), wherein the groups of sub retroreflection elements are disposed on one main retroreflection element that is divided by three side surfaces mutually crossing at almost right angles by means of 3-directional V-shaped parallel groove groups that are disposed on a main plane (S-S'), mutually cross and have substantially symmetrical sections.

Description

Composite triangular pyramid cube corner retroreflective sheeting and retroreflector

technical field

The invention relates to a triangular pyramid cube corner retroreflective sheet and a retroreflective object with a novel structure. Specifically, the present invention relates to a cube-corner retroreflective sheeting and a retroreflective object in which triangular pyramid-shaped reflective elements of a novel structure are arranged in the most densely packed manner.

In detail, the present invention relates to road signs (general traffic signs and reflective signs), pavement markers (pavement maker), engineering signs and other signs, number plates of vehicles such as automobiles and motorcycles, and stickers attached to trucks and trailers. Triangular pyramid cube corner retroreflective elements useful in reflective tapes for car bodies, clothing, life-saving appliances and other safety equipment, signs such as billboards, visible light, laser or infrared light reflective sensors, etc. Cube-corner retroreflective sheeting and retroreflectors composed of triangular pyramidal reflective elements).

Specifically, it relates to a triangular-pyramidal cube corner retroreflective sheeting and retroreflective object, which is characterized in that it includes a composite cube corner retroreflective element formed in the following manner, that is, three directions through which the section is basically symmetrical The V-shaped parallel groove groups intersect each other, and at least two or more triangular pyramid cube corner retroreflective element groups divided by three reflective sides that cross each other approximately at right angles are arranged in the most densely packed manner toward the shared subplane (SH -SH) protrudes on one side, and by intersecting the V-shaped parallel groove groups arranged in the main plane (S-S) and having a substantially symmetrical cross-section in three directions, the sub-reflecting element group is arranged in three directions. On a main reflective element divided by reflective sides that cross each other approximately at right angles.

Background technique

Conventionally, retroreflective sheeting and retroreflective objects that reflect incident light toward a light source are known, and such sheets utilizing their retroreflective properties can be widely used in the above-mentioned application fields. Among them, compared with retroreflective sheeting and retroreflective objects using traditional miniature glass beads, cube corner retroreflective sheeting and retroreflective objects using the retroreflective principle of cube corner retroreflective elements such as triangular pyramid reflective elements, Its light retroreflection efficiency is particularly excellent, and its use is expanding year by year due to its excellent retroreflection performance.

However, light incident on the reflective side surface at an angle smaller than the critical angle satisfying the internal total reflection condition determined by the ratio of the refractive index of the transparent medium constituting the retroreflective element to the refractive index of air is not reflected at the interface of the reflective side surface. Total reflection, and will pass through the back of the reflective side, so there is a disadvantage that the incident angle characteristics of retroreflective sheeting and retroreflective objects using triangular pyramid cube corner retroreflective elements will usually be deteriorated. That is to say, good retroreflective efficiency is shown in the range of small angles between the surface of the retroreflective sheeting and the incident light, but with the increase of the incident angle, the retroreflective efficiency will drop sharply.

In addition, because the triangular pyramid type retroreflective element can reflect the light along the direction of light incident on almost the entire surface of the element, because the reflected light will not be excessively divergent due to spherical aberration and other reasons like the micro glass bead type reflective element , so it has excellent retroreflective properties.

However, in terms of practicality, when the light emitted by the headlights of the car is retroreflected on the traffic sign, it is easy to appear that the retroreflected light with too narrow divergence angle is difficult to reach the driver's eyes at a position away from its optical axis. . This disadvantage is particularly noticeable when the distance between the vehicle and the traffic sign is particularly close, because the viewing angle defined by the angle formed by the incident axis of the light and the viewing axis connecting the driver and the reflection point increases. That is to say, there is a problem that the viewing angle characteristics of known conventional triangular pyramid type cube corner retroreflective elements are generally deteriorated.

In addition, the triangular pyramid cube corner retroreflective element is formed by three reflective sides, and its retroreflective performance changes with the direction (called azimuth) of the incident light on the reflective side, so when setting the retroreflective sheet , the orientation of the component must be constant. In this way, the retroreflective performance of the triangular pyramid cube corner retroreflective element is dependent on the azimuth angle, that is, there is a problem in the azimuth angle characteristic.

In addition, conventional triangular pyramidal cube corner retroreflective elements are known to have an optical axis defined as passing through the apex of the triangular pyramidal cube corner retroreflective element and the three intersecting surfaces forming the retroreflective element at approximately right angles. axes equidistant from the reflection sides.

Regarding the improvement of the incident angle characteristics or observation angle characteristics of such cube corner retroreflective sheeting and retroreflective objects, especially triangular pyramidal cube corner retroreflective sheeting and retroreflective objects, many schemes have been proposed so far, and research has been carried out. Various research improvements.

For example, in US Pat. No. 2,481,757 to Jungersen, retroreflective elements of various shapes are provided on a sheet. The triangular pyramid reflective elements exemplified in the above-mentioned U.S. patents are triangular pyramid reflective elements whose apex is located at the center of the triangle on the bottom surface and whose optical axis is not inclined, and triangular pyramid reflectors whose apex is not located at the center of the triangle on the bottom surface and whose optical axis is inclined. It is a case of efficiently reflecting light to an approaching car (improvement of the incident angle characteristic).

In addition, as the dimensions of the triangular pyramid reflective element, the depth of the element is stated to be within 1/10 inch (2.540 μm). In addition, in the accompanying drawing 15 of this U.S. patent, the pair of triangular pyramid reflective elements whose optical axis (as described below) is inclined to the positive (+) direction is illustrated. The inclination angle (θ) of the optical axis was obtained from the ratio of the length of the side to the short side, and it was estimated to be about 6.5°.

However, in the U.S. patent of Jungersen mentioned above, there is no specific disclosure of the minimal triangular pyramid reflective element mentioned later. In addition, in order to provide excellent observation angle characteristics or incident angle characteristics, what size and optical axis inclination the triangular pyramid reflective element should have , which is neither documented nor suggested.

In addition, the retroreflective sheeting and retroreflective objects described in U.S. Patent No. 3,712,706 of Stamm are a so-called regular triangular pyramidal cube corner retroreflective element whose base triangular shape on the sheet is an equilateral triangle. Configured so that its bottom surface is most densely packed on the shared surface. In the U.S. patent of Stamm, the reflective surface of the reflective element is vapor-deposited with metal such as aluminum, so that the incident light is specularly reflected, and the incident angle is increased, thereby improving the problem of retroreflective efficiency decline and the future An undesirable condition in which light incident at an angle satisfying the condition of total internal reflection passes through the interface of a component without being retroreflected.

However, in the above-mentioned Stamm's proposal, as a means for improving the wide-angle performance, the following disadvantages are likely to occur, that is, the appearance of the obtained retroreflective sheeting and retroreflective objects becomes dark because the specular reflection layer is provided on the reflective side. , Aluminum, silver and other metals used in the specular reflection layer are oxidized due to the immersion of water and air during use, and are prone to decrease in reflective brightness. In addition, nothing is described about means for improving wide-angle performance by inclination of the optical axis.

In addition, the retroreflective sheeting and retroreflective objects described in European Patent No. 137,736B1 by Hoopman are a pair of inclined triangular pyramidal cube corners in which the shape of the base triangle on the sheeting is an equilateral triangle. The retroreflective elements are arranged rotated 180° relative to each other with their base surfaces most densely packed on the common surface. The inclination of the optical axis of the triangular pyramid cube corner retroreflective element described in this patent is in the negative (-) direction described in this specification, and the inclination angle is about 7° to 13°.

In addition, the retroreflective sheeting and retroreflective objects disclosed in U.S. Patent No. 5,138,488 of Szczech are: similarly, the shape of the base triangle on the sheet is an inclined triangular pyramidal cube of two equilateral triangles. The corner retroreflective elements are arranged such that their bases are most densely packed on the common plane. In this U.S. patent, the optical axis of the triangular pyramidal reflective element is inclined to the side direction shared by two triangular pyramidal reflective elements facing each other, that is, the positive (+) direction described later. The inclination angle is about 2°-5°, and the size of the element is 25 μm-100 μm.

In addition, in European Patent No. 548,280B1 corresponding to the above-mentioned patent, it is described that the inclination angle of the inclination direction of the optical axis is about 2° to 5°, including the common side of the two elements constituting a pair and perpendicular to the common plane. The distance from the apex of the element and the intersection point of the optical axis of the element and the common plane and the above-mentioned vertical plane are not equal, and the size of the element is 25 μm to 100 μm.

As mentioned above, in Szczech's European Patent No. 548,280B1, the inclination of the optical axis is in the range of about 2° to 5° including both positive (+) and negative (−). But, in the embodiment of above-mentioned U.S. patent and European patent of Szczech, only disclosed that the inclination angle of optical axis is (-) 8.2 °, (-) 9.2 ° and (-) 4.3 °, the height (h) of element is 87.5 μm triangular pyramid reflective element.

In addition, as a proposal to improve the viewing angle characteristics, for example, in U.S. Patent No. 4,775,219 of Appeldorn, the V-shaped grooves forming the elements are asymmetrical, compared to the theoretical V-shaped grooves forming the cube corners. There is a slight deviation in the angle. In addition, it was tested to improve the observation angle characteristic by periodically changing the deviation that causes asymmetry with the adjacent V-shaped grooves.

However, periodically changing the angles of adjacent V-shaped grooves increases the difficulty of mold processing. Even if this difficulty can be overcome, the deviation combinations that can be given are limited, and the reflected light cannot be uniformly diffused. In addition, even for one V-shaped groove direction, it is necessary to prepare a plurality of processing tools such as diamond tips for forming V-shaped grooves. In addition, high-precision processing technology is required to form V-shaped grooves in an asymmetric form.

In addition, U.S. Patent No. 5,171,624 of Walter discloses a triangular pyramidal retroreflective method that uses a processing tool having a curved cross-sectional shape to form a reflective side surface having a constant quadratic curved cross-sectional shape. element. In the triangular pyramid retroreflective element formed with such a quadratic curved reflective side surface, the retroreflected light can be appropriately diffused and the observation angle characteristics can be improved, but it is very difficult to manufacture a processing tool with such a curved cross-sectional shape . Therefore, considering the machining difficulty of the tool, it is difficult to obtain the quadratic surface based on the conceived design.

Improvement of viewing angle characteristics is attempted in US Patent No. 5,565,151 by Nilsen, in which part of the reflective side is cut away, thereby forming a triangular prism-shaped part and a new reflective side, thereby promoting divergence of retroreflected light.

However, in Nielsen's invention, there is little specific description of which shape of the triangular prism arrangement is preferred or at which angle the new reflective side is preferably formed. In addition, special tools are required to cut away part of the reflective sides to form the triangular prisms. In addition, the newly formed triangular prism-shaped element does not have a retroreflective function, but simply disperses light in various directions to obtain diffusion of retroreflected light.

Additionally, tests disclosed in U.S. Patent No. 4,202,600 to Bruke and U.S. Patent No. 5,706,132 to Nestegard et al. The regions of the element group are combined so that the retroreflection of light incident at different azimuth angles becomes uniform.

In summary, as shown in FIG. 6 of the present invention, well-known U.S. Patent No. 2,481,757 to Jungersen, U.S. Patent No. 3,712,706 to Stamm, European Patent No. 137,736B1 to Hoopman, and U.S. Patent No. 5,138,488 to Szczech, European Patent No. 548,280B1 and other conventional triangular pyramidal cube corner retroreflective elements all have the following disadvantages, that is, the points where the bottom surfaces of the plurality of triangular pyramidal reflective elements that constitute the core portion of light incidence and reflection are located on the same plane and the opposing pair of elements The points that form a similar shape and have the same height of the elements are common, so if any of the incident angle characteristics of the retroreflective sheeting and retroreflective objects composed of triangular pyramidal reflective elements with the bottom surface on the same plane are degraded, that is, if As the incident angle of light on the triangular pyramid reflective element increases, the retroreflected brightness decreases sharply.

In addition, in the above-mentioned well-known U.S. Patent No. 4,775,219 of Appeldorn, U.S. Patent No. 5,171,624 of Walter, and U.S. Patent No. 5,565,151 of Nilsen, it is also proposed to use various methods to improve the observation angle characteristics. But wherein any invention all has shortcoming such as tool manufacture and mold processing difficulty.

Contents of the invention

The object of the present invention is to improve the problems of the above-mentioned known traditional triangular pyramid cube corner retroreflective sheeting and retroreflectors in the characteristics of incident angle, observation angle and azimuth angle.

Another subject of the present invention is to improve road signs (general traffic signs and reflective signs), pavement markers (pavement maker), engineering signs, etc. Number plates of motorcycles and other vehicles, reflective tapes attached to the body of trucks and trailers, safety equipment such as clothing, life-saving appliances, signs such as billboards, reflectors such as visible light, laser or infrared light reflective sensors, etc. retroreflective properties.

When the present invention improves the incident angle characteristics, observation angle characteristics and azimuth characteristics of the above-mentioned known traditional retroreflective elements, it is realized by having a composite cube corner retroreflective element, and its formation method is as follows: the passing section is basically symmetrical The V-shaped parallel groove groups in three directions of the shape intersect each other, and at least two or more triangular pyramid cube corner retroreflective element groups divided by three reflective sides that cross each other approximately at right angles are arranged in the most densely packed manner to share One side of the sub-plane (SH-SH) protrudes, and the group of V-shaped parallel grooves arranged on the main plane (S-S) and having a substantially symmetrical cross-section in three directions cross each other, and the sub-reflector group is arranged On a triangular pyramidal cube corner retroreflective element divided by three reflective sides that cross each other approximately at right angles. The use of such composite elements facilitates in particular the improvement of the viewing angle characteristics.

In addition, the aforementioned improvements are achieved by the use of the aforementioned composite cube corner retroreflective elements in which the secondary plane (SH-SH) is parallel to the primary plane (S-S), the use of which composite elements particularly facilitates improved viewing angle characteristics.

In addition, such composite elements realized by using the above-mentioned composite cube-corner retroreflective elements with the secondary reflective element and/or the primary reflective element having an inclined optical axis also contribute particularly to an improved angle of incidence characteristic.

In addition, the above-mentioned improvements are not parallel to at least one group of the bottom edges of the three directions forming the main reflector element and the bottom edges of the other three directions forming the sub-reflector element, preferably one group of directions This is achieved by the aforementioned composite cube-corner retroreflective elements whose bottom edge is perpendicular, the use of which composite elements particularly facilitates improved azimuth characteristics.

In addition, the above-mentioned improvement can effectively improve any one of the incident angle characteristics, observation angle characteristics, and azimuth angle characteristics by combining the above-mentioned known conventional improvement techniques.

The triangular-pyramidal cube-corner retroreflective sheeting and retroreflective objects formed by the composite cube-corner retroreflective element of the present invention can obtain excellent incident angle characteristics, observation angle characteristics and azimuths that cannot be obtained in known traditional retroreflective elements corner properties.

Description of drawings

FIG. 1 is a diagram showing a known conventional retroreflective element.

Fig. 2 is a diagram showing a known conventional retroreflective element.

Fig. 3 is a diagram showing a retroreflective element of the present invention.

Fig. 4 is a diagram showing a collection of retroreflective elements of the present invention.

Fig. 5 is a diagram showing a retroreflective element of the present invention.

Fig. 6 is a diagram showing a retroreflective element of the present invention.

Fig. 7 is a diagram showing a retroreflective element of the present invention.

Fig. 8 is a diagram showing a collection of retroreflective elements of the present invention.

Fig. 9 is a diagram showing a retroreflective element of the present invention.

Fig. 10 is a diagram showing a collection of retroreflective elements of the present invention.

Fig. 11 is a diagram showing a retroreflective element of the present invention.

Detailed ways

In describing the best mode for carrying out the present invention, a known conventional triangular pyramid type cube corner retroreflective element (hereinafter also referred to as a retroreflective element) will be described with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating a known conventional triangular-pyramidal cube corner retroreflective element, showing a pair of retroreflective elements (A-B-C1-H1, A-B-C2-H2) sharing a base (A-B) but facing each other. The reflective element shown in Figure 1 is a pair of so-called regular triangular pyramidal cube corner retroreflective elements whose bottom surface shape (A-B-C1, A-B-C2) is an equilateral triangle. Parallel groove groups (x, y, and z directions) intersect each other at an angle of 60°, and three reflective sides (a1, b1, c1 and a2, b2, c2) of the same shape that cross each other at approximately right angles are right-angled equilateral triangles. ) are divided, and these reflective element pairs are arranged on a common plane (S-S).

The optical axis of the retroreflective element in FIG. 1 intersects the common plane (S-S) perpendicularly without being inclined.

Also, because the shape of the element is typically triangular, its retroreflective properties vary depending on which direction (also called azimuth) the light is incident. The retroreflective performance at incidence parallel to the base (A-B) in FIG. 1 is different from that at right angles. As such, the azimuthal dependence of retroreflective performance is a problem with triangular pyramid cube corner reflective elements.

In addition, the size of the element in FIG. 1 can be represented by the height (h, also referred to as element height hereinafter) from the vertex to the common plane (S-S). When light incident on a reflective element is retroreflected, it is retroreflected in a diffuse manner due to divergence caused by a diffraction effect depending on the size of the element. In other words, the smaller the element height (h), the greater the diffraction effect, which can diffuse the retroreflected light and obtain an improvement in the viewing angle characteristics, but the divergence effect will become smaller in a reflective element with an excessively small element height (h). If it is too large, its retroreflection performance will be reduced.

In addition, a specular reflective layer may be provided on the reflective side surfaces (a1, b1, c1 and a2, b2, c2) of the reflective element. Various metallic reflective substances, such as aluminum, silver, nickel, and copper, can be used on the specular reflection layer. The following disadvantages will occur in the reflective element provided with such a specular reflective layer: since the incident light at an angle greater than the critical angle on the reflective side can also be reflected, although the incident angle characteristics can be improved, the retroreflective sheet and the retroreflective The appearance is darkened.

FIG. 2 is likewise a diagram illustrating a known conventional triangular-pyramidal cube-corner retroreflective element with a tilted optical axis (hereinafter also referred to as a tilted reflective element).

In the angled retroreflective element shown in Figure 2, the distance (p) between the apex and the intersection point (P) of the perpendicular to the common plane (S-S) and the base (A-B) and the intersection of the optical axis and the common plane (S-S) are shown A component whose difference (q-p) between the distance (q) of the point (Q) and the base (A-B) is not zero.

In particular, what is shown in FIG. 2 is a so-called positively inclined element in which (q-p) is positive. Since such an inclined reflective element improves retroreflection performance toward an inclined optical axis, the incident angle characteristic is excellent. Regardless of whether (q-p) is positive (positively inclined reflective element) or negative (negatively inclined reflective element), the improvement of the incident angle characteristic according to the principle of such an inclination of the optical axis can be realized.

Fig. 3 shows a composite triangular-pyramid cube-corner retroreflective element of the present invention whose bottom surface is an equilateral triangle and whose optical axis is not inclined.

In Fig. 3, by crossing V-shaped parallel groove groups in three directions with substantially symmetrical cross-sections, the four sub-reflecting element groups divided by three reflective side surfaces crossing each other at approximately right angles are arranged in the most densely packed manner, so that It protrudes to one side on the common secondary plane (SH-SH). The element height defined by the distance from the vertices of these secondary reflective elements to the common secondary plane (SH-SH) is denoted by hs.

The sub-reflecting element group is arranged on one main reflecting element, and the main reflecting element has an equilateral triangle (A-B-C1, A-B-C2) on the bottom surface, and the cross-section arranged on the main plane (S-S) is basically symmetrical. Groups of V-shaped parallel grooves in three directions intersect each other and are divided by three reflective side surfaces that intersect each other approximately at right angles.

For the main reflective element, the distance from the imaginary vertex (Hm) formed by the intersection of the extended surfaces of the three reflective side surfaces forming the element to the main plane (S-S) is hm. In addition, the sub-plane (SH-SH) shared by the sub-reflector group is located at a distance of hp from the imaginary vertex (Hm).

In Fig. 3, the bases of the three directions forming the main reflective element are all parallel to the bases of the other three directions forming the sub-reflecting element, and the triangles forming the bases are similar in shape. The inclination angles of the axes are all 0°.

In the composite reflective element shown in Fig. 3, effective retroreflective performance is represented by the main reflective element, and at the same time, the divergence of reflected light is generated by the sub-reflective element according to the refraction effect, and the observation angle characteristic is improved.

Fig. 4 is the composite triangular pyramidal cube corner retroreflective elements shown in Fig. 3 sharing the bottom edge of the main reflective element while being most densely packed. The main reflective element is formed by V-shaped parallel groove groups (x, y, z) in three directions that are substantially symmetrical in cross-section, and the V-shaped parallel groove groups in three directions forming the sub-reflective element are also similar to those used to form the main reflective element. The V-shaped parallel groove groups (x, y, z) are parallel, and the bases of these V-shaped grooves are located on the common sub-plane (SH-SH).

In the composite retroreflective element shown in FIG. 5 , four sub-reflective elements with the same optical axis inclination and a smaller element height are provided on a positively inclined main reflective element whose optical axis (q-p) is inclined to the positive direction. In such a composite retroreflective element, it is possible to improve the incident angle characteristic by the inclination of the optical axis, and to realize the improvement of the observation angle characteristic by the sub-reflective element.

In the compound retroreflective element of Fig. 5, no matter the inclination direction of the optical axis (q-p) is positive or negative, the improvement of the incident angle characteristic can be realized, but the inclination angle is preferably such that the secondary reflective element and/or the main reflective element The optical axis of the reflective element is inclined by 1° to 13°, preferably by 1.5° to 7°.

When the inclination angle of the optical axis is less than 1°, the improvement of the incident angle characteristic is not significant, and the retroreflectivity in the front direction tends to be degraded in a reflective element having a large inclination of more than 13°.

Same as Fig. 3, what Fig. 6 shows is a kind of bottom surface shape of the present invention is regular triangle, optical axis is not inclined compound triangular pyramid cube corner retroreflective element form, but the quantity of secondary reflective element on a main reflective element There are 16 elements, and they are elements whose height is smaller than that of the sub-reflecting element shown in FIG. 3 .

Like the composite reflective element shown in Figure 3, in the composite reflective element of Figure 6, the bases in the three directions forming the main reflective element are all parallel to the bases in the other three directions forming the sub-reflective element, forming the base The triangles of are similar shapes, and the inclination angle of the optical axis in any element is 0°.

In addition, Fig. 7 shows a compound triangular pyramidal cube corner retroreflective element of the present invention whose base shape is an equilateral triangle and the optical axis is not inclined, but the number of secondary reflective elements with complete shapes on one main reflective element is 6 One, the other secondary reflective elements are cut off from the reflective sides of the primary reflective element.

In addition, the bases in three directions forming the base of the main reflector and the bases in a group of directions forming the bases in the other three directions of the sub-reflector are perpendicular to each other. The arrangement directions of the opposite bottom sides of the reflective elements are perpendicular to each other.

Figure 8 shows the most densely packed arrangement of the composite triangular pyramidal cube corner retroreflective elements shown in Figure 7 sharing the base of the main reflective element. The main reflection element is formed by a group of V-shaped parallel grooves (x, y, z) in three directions with a substantially symmetrical cross section. The V-shaped parallel groove groups forming any three directions of the sub-reflector element are not parallel to the V-shaped parallel groups (x, y, z) forming the main reflector element, and the bottom edges of these V-shaped grooves are located in a common sub-plane ( SH-SH). In addition, the base of one V-shaped groove forming the sub-reflecting element is perpendicular to the group (x) of V-shaped parallel grooves forming the main reflecting element.

The composite reflective elements shown in Figures 7 and 8 are formed by combining the main reflective element and the secondary reflective element whose arrangement direction is at right angles, which can improve the azimuth angle characteristics and observation angle characteristics of the retroreflection performance. In addition, if both the main reflection element and the sub-reflection element use a reflection element with an inclined optical axis, it is also possible to improve the incident angle, which is preferable. In addition, the bases of the three directions forming the main reflector may not be parallel to the bases of any direction group forming the bases of the other three directions of the sub-reflecting element.

No matter whether (q-p) is positive or negative, the inclination direction of the optical axis of the composite retroreflective element shown in Fig. 7 and Fig. 8 can realize the improvement of the incident angle characteristic, but for its inclination angle, preferably the sub-reflective element and/or The main reflective element has a compound retroreflective element whose optical axis is inclined by 1-13°, preferably the optical axis is inclined by 1.5-7°.

Fig. 9 shows another form of the composite retroreflective element pair in the present invention. Same as Fig. 3 and Fig. 6, what Fig. 9 shows is that a kind of bottom surface shape of the present invention is equilateral triangle, optical axis is not inclined compound triangular pyramid cube corner retroreflective element form, but in the main reflective element (A-C1 -B and A-C2-B) The number of sub-reflective elements formed is four.

The main reflection elements (A-C1-B and A-C2-B) in FIG. 9 are formed on a common plane (S-S) defined by a plurality of V-shaped grooves (x, y, z). In addition, a plurality of sub-reflective elements are formed by a plurality of V-shaped grooves (xh, yh, zh), and exist on another shared plane (SH-SH) defined by the plurality of V-shaped grooves (xh, yh, zh). superior. In addition, the shared plane (S-S) exists at a lower position than the other shared plane (SH-SH). The plurality of V-shaped grooves (x, y, z) are formed at equal intervals to the other plurality of V-shaped grooves (xh, yh, zh), and only the depth of the grooves is different.

Like the composite reflective element shown in Fig. 3 and Fig. 6, the composite reflective element in Fig. 9 is formed such that the bases of the main reflective element in three directions are parallel to the bases of the other three directions forming the sub-reflective element, The triangles forming the bases are similar shapes, and the inclination angle of the optical axis is 0° in either element.

Shown in FIG. 10 is an assembly diagram of the pair of composite retroreflective elements shown in FIG. 9 . In FIG. 10, the composite triangular pyramidal cube corner retroreflective elements shown in FIG. 9 share the base of the main reflective element and are most densely packed. The multiple V-shaped grooves (xh, yh, zh) forming the multiple sub-reflectors shown in FIG. 10 do not form continuous straight and curved tracks. The trajectory can be selected to be different from that of other secondary reflective elements formed on the adjacent primary reflective element. Thus, being able to adopt various trajectories is effective in improving the observation angle characteristic.

Fig. 11 shows another form of the pair of composite retroreflective elements of the present invention. Same as Fig. 9, what Fig. 11 represented is a kind of bottom surface shape of the present invention is regular triangle, optical axis is not inclined compound triangular pyramid cube corner retroreflective element form, but in the main reflective element (A-C1-B and The number of sub-reflective elements formed on A-C2-B) is nine.

The main reflection elements (A-C1-B and A-C2-B) in FIG. 11 are formed on a common plane (S-S) defined by a plurality of V-shaped grooves (x, y, z). In addition, a plurality of sub-reflective elements are formed by a plurality of V-shaped grooves (xh, yh, zh), and exist on another common plane (SH-SH) defined by the plurality of V-shaped grooves (xh, yh, zh). superior. In addition, the shared plane (S-S) exists at a lower position than the other shared plane (SH-SH). In addition, a plurality of V-shaped grooves (x, y, z) and other plurality of V-shaped grooves (xh, yh, zh) are formed at equal intervals, and only the depth of the grooves is different.

Like the composite reflective element shown in Figure 9, in the composite reflective element shown in Figure 11, the bases in three directions forming the main reflective element are parallel to the bases in the other three directions forming the sub-reflective element, The triangles forming the bases are similar shapes, and the inclination angle of the optical axis is 0° in either element.

The inclination angle of the optical axis of the composite reflective element shown in FIGS. 9 to 11 and the main element and sub-reflective element forming the composite reflective element is 0°. However, the optical axes of the composite reflective elements shown in FIGS. 9 to 11 and the main elements and sub-reflective elements forming the composite reflective elements may be inclined in the positive or negative direction. The inclination angle of the optical axis is preferably a compound retroreflective element in which the inclination angle is 1-13°, and the inclination angle of the optical axis is preferably 1.5-7°. It is preferable that the depths of the V-shaped grooves (xh, yh, zh) forming the sub-element whose optical axis has an inclination angle of 0° be equal.

In addition, the depths of the V-shaped grooves (xh, yh, zh) forming the sub-reflector with an inclined optical axis may not be equal. In the sub-reflector whose optical axis is inclined in the opposite direction, it is preferable to form the depth of the V-shaped grooves in the xh direction to be shallower than the depths of the V-shaped grooves in the yh and zh directions. The depth of the V-shaped grooves is preferably formed deeper than the depths of the V-shaped grooves in the yh and zh directions.

The secondary plane (SH-SH) and the main plane (S-S) of the composite reflective element in the present invention do not need to be parallel in particular. When forming a large composite reflective element, it can also be made into a non-parallel shape. When shooting a small compound reflective element, it is preferable that the secondary plane (SH-SH) is parallel to the main plane (S-S), because it can facilitate the formation of the element.

The size of the main reflective element of the composite reflective element of the present invention is preferably such that the distance (hm) from the imaginary vertex (Hm) formed by the intersection of the extended planes of the three reflective side surfaces of the main reflective element to the main plane (S-S) Greater than 50 μm. When the distance (hm) of the main reflector is less than 50 μm, the size of the sub-reflector that can be formed on the main reflector becomes too small or the divergence of reflected light becomes too large, and the retroreflection performance decreases, which is not preferable.

In addition, in the case of a composite reflective element used in a retroreflective sheeting, the distance (hm) is preferably 50 μm or more, more preferably 80 to 300 μm. When the distance (hm) of the main reflective elements exceeds 300 μm, the thickness of the retroreflective sheeting increases, and a flexible sheet cannot be obtained.

The difference between the distance (hs) from the vertex (Hs) of the secondary reflective element to the secondary plane (SH-SH) in the present invention and the distance (hm) from the imaginary vertex (Hm) of the main reflective element to the main plane (S-S) The ratio (hs/hm) is preferably 0.1 to 0.5, more preferably 0.1 to 0.3.

When the ratio (hs/hm) is less than 0.1, the size of the secondary reflective element becomes too small, and when it is greater than 0.5, the size of the secondary reflective element becomes too large, and the area ratio of the effective reflective side of the main reflective element becomes too large. Small, so there will be a decrease in retroreflection.

The ratio of the distance (hm) from the imaginary vertex (Hm) of the main reflective element to the main plane (S-S) to the distance (hp) from the imaginary vertex (Hm) of the main reflective element to the secondary plane (SH-SH) (hp/hm ) is preferably 0.1 to 0.9, more preferably 0.3 to 0.5.

When the ratio (hp/hm) is less than 0.1, the shape of the sub-element becomes too small, and it is difficult to improve the observation angle characteristics produced by the sub-reflection element. When it is greater than 0.9, the area ratio of the reflection side of the main reflection element becomes too high. Small, so there will be a decrease in retroreflection performance.

As the triangular-pyramid cube-corner retroreflective element that can be used in the composite reflective element of the present invention, various retroreflective elements described in detail in the background art or other known retroreflective elements can be used, thereby further improving the retroreflective performance. .

In addition, the composite reflective element in the present invention can be produced by the known traditional spinning method, scribing method and planing method. The method of producing the reflective element can be produced by forming V-shaped grooves in three directions by the above-mentioned machining method. The order of manufacture can also be any of the following methods, that is, after forming the secondary reflective element, then form a deep groove to form the main element, or after forming the main reflective element, then form a shallow groove in the main reflective element. Method for forming subcomponents.

It is preferable that the three reflective side surfaces of each cube corner reflective element forming the composite reflective element of the present invention intersect each other substantially perpendicularly, but from the viewpoint of improving the observation angle characteristics by making the reflected light diverge slightly, it is also possible to The angles perpendicular to each other are given a deviation (prism apex angle deviation). To this end, the following methods can be adopted: giving deviations to the groove angles of the V-shaped grooves in each direction, providing the side walls of the V-shaped grooves in slightly curved curved cross-sections, and making the bottom traces of the V-shaped grooves in a bent line shape. There are methods such as moving and making the reflective side surface into a polyhedron, or moving the bottom track of the V-shaped groove in a curved line to make the reflective side surface into a curved surface.

The plurality of V-shaped grooves (xh, yh, zh) forming the plurality of sub-reflectors shown in the present invention do not form continuous straight and curved trajectories. The trajectory may be selected to be different from that of other secondary reflective elements formed on the adjacent primary reflective element. In this way, various trajectories can be employed, which is effective in improving the observation angle characteristics. A plurality of V-shaped grooves (xh, yh, zh) forming the sub-reflective element formed on the main reflective element can adopt different methods respectively, and give deviations to the groove angles of the V-shaped grooves in each direction, and the following methods can be independently adopted : The groove angle of the V-shaped groove in each direction is deviated according to various reflective elements, the cross-sectional shape of the V-shaped groove is slightly curved, and the bottom trajectory of the V-shaped groove is moved in a curved line. The reflective side is made into a polyhedron, or the bottom track of the V-shaped groove is moved in a curved shape to make the reflective side into a curved surface, etc.

In particular, it is preferable to make the reflective side surface into a polyhedron by moving the bottom track of the V-shaped groove forming the sub-reflective surface in a curved line. Or in particular, it is preferable to use a method such as moving the bottom track of the V-shaped groove forming the sub-reflecting surface in a curved shape to make the reflecting side surface into a curved surface.

In addition, at least one direction of the track of the bottom of the V-shaped groove in three directions forming the sub-reflecting element contained in one main reflecting element is preferably different from the same one forming the sub-reflecting element contained in the adjacent main reflecting element. The track of the V-shaped groove in the direction. The following methods can be enumerated: for example, the bottom track of the V-shaped groove of the sub-reflector included in one main reflector is moved in a bent line shape to make the reflective side into a polyhedron and make the sub-reflector included in the adjacent main reflector. The bottom track of the V-shaped groove in the same direction of the component moves in a curved shape and the reflective side is made into a curved surface. A retroreflective element having such a shape is excellent in viewing angle characteristics. When the track of the bottom of the groove is a meander line or a curved line, it is preferable to give the straight line a deviation of about 0.05 to 1% from the length of the bottom of the reflective element.

In addition, the cross-sectional shape of at least one of the three directions of the V-shaped grooves forming the sub-reflecting element is preferably different from the cross-sectional shape of the V-shaped grooves in the same direction forming the sub-reflecting elements included in the adjacent main reflecting element. The so-called cross-sectional shape mentioned here refers to a V-shaped cross-sectional shape with a slight deviation in the groove angle, or a V-shaped cross-sectional shape that is slightly curved and curved. For example, there may be a method of making the V-shaped cross-sectional shape of a sub-reflecting element included in one main reflecting element different from the cross-sectional shape of a V-shaped groove in the same direction forming a sub-reflecting element included in an adjacent main reflecting element. A retroreflective element having such a shape is excellent in viewing angle characteristics.

In addition, the resins and colorants that can be used in the composite reflective element in the present invention are conventional products and can be appropriately used without any particular limitation. In addition, the structure of the retroreflective sheeting and the retroreflective material when used as the retroreflective sheeting and the retroreflective material can also appropriately adopt known conventional product structures.

Example

Hereinafter, the details of the present invention will be described in more detail based on examples, but it goes without saying that the present invention is not limited to the examples.

<Coefficient of retroreflection>

The coefficient of retroreflection described in this specification was measured by the method demonstrated below from an Example. Using the "Model 920" manufactured by Gunma-Syenty Figure Co., Ltd. as a retroreflection coefficient measuring device, according to ASTM E810-91, at observation angles of 0.2° and 0.5°, and incident angles of 5°, 10°, 20° and 30° Under the angle condition, measure the retroreflection coefficient of the 100mm×100mm retroreflective sheeting for 5 appropriate positions, and take the average value as the retroreflective coefficient of the retroreflective sheeting.

<Comparative example 1>

Forming a tilted triangular pyramid cube corner retroreflective element having the shape shown in Fig. 2 with the optical axis tilted +7°, that is, the element height (h) is 130 μm, and the inner angle of the parallel V-shaped grooves in the x direction is 56.5° , the repetition pitch is 311.7μm, the internal angle of the parallel V-shaped grooves in the y and z directions is 77.0°, the repetition pitch is 266.8μm, and the intersection angle between the x direction and the y and z directions is 64.7°. Cutting method to form a brass mold with a plurality of inclined triangular pyramid cube corner retroreflective elements.

Using this brass master, a nickel sulfamate solution with a concentration of 55% was used for electroplating to form a mold for forming concave cube corners made of nickel and whose shape was reversed. The production of the retroreflective sheeting (comparative sample 1) is as follows: Using this molding die, under the conditions of molding temperature 200 ° C and molding pressure 50 kg/cm2, a polycarbonate resin sheet (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) "U-Piron H3000") is compression molded, cooled to 30°C under pressure, and the resin sheet is taken out to make the most densely packed composite cube corner retroreflective elements made of polycarbonate resin on the surface. A retroreflective sheeting (comparative sample 1) configured in the ground.

<Example 1>

Adopt the method identical with comparative example 1, obtain the shape shown in Fig. 3, promptly be +7 ° at the inclination angle of optical axis, the imaginary vertex ( Hm) to the main plane (S—S) distance (hm) is 130 μm on the main reflective element, the composite circuit of 4 sub-element groups with an inclination angle of the optical axis of +7° and a height (hs) of 30 μm radio components.

The distance (hs) from the vertex (Hs) of the secondary reflective element in the composite reflective element to the secondary plane (SH-SH) and the distance from the imaginary vertex (Hm) of the main reflective element to the main plane (S-S) The ratio (hs/hm) of (hm) is 0.23, the distance (hp) from the imaginary vertex (Hm) of the main reflective element to the secondary plane (SH-SH) is 50 μm, and the ratio (hp/hm) is 0.385.

Using the same compression molding method as in Comparative Example 1, a retroreflective sheeting (invention sample 1) in which a plurality of composite cube-corner retroreflective elements made of polycarbonate were arranged in the most densely packed manner was manufactured.

<Example 2>

Adopt the method identical with comparative example 1, obtain the shape shown in Fig. 6, promptly be +7 ° at the inclination angle of optical axis, the imaginary vertex ( Hm) to the main plane (S—S) distance (hm) is 130 μm on the main reflective element, set 16 sub-element groups with an inclination angle of the optical axis of +7° and a height (hs) of 30 μm. radio components.

The distance (hs) from the vertex (Hs) of the secondary reflective element in the composite reflective element to the secondary plane (SH-SH) and the distance from the imaginary vertex (Hm) of the main reflective element to the main plane (S-S) The ratio (hs/hm) of (hm) is 0.23, the distance (hp) from the imaginary vertex (Hm) of the main reflector to the sub-plane (SH-SH) is 65 μm, and the ratio (hp/hm) is 0.5.

Using the same compression molding method as in Comparative Example 1, a retroreflective sheeting (invention sample 2) in which a plurality of composite cube-corner retroreflective elements made of polycarbonate were arranged in the most densely packed manner was produced.

<Example 3>

Adopt the method identical with comparative example 1, obtain the shape shown in Fig. 9, be that the inclination angle of optical axis is-6 °, the imaginary vertex ( A composite retroreflective element in which four sub-element groups with an inclination angle of -6° of the optical axis of the element and a height (hs) of 70 μm are installed on the main reflective element whose distance (hm) from the main plane (S-S) is 180 μm . Note that the heights of the four sub-reflectors formed are slightly different, so the height between the apex of the tallest sub-reflector located in the center and the sub-plane (SH-SH) is defined as hs.

The difference between the distance (hs) from the vertex (Hs) of the secondary reflective element in the composite reflective element to the secondary plane (SH-SH) and the distance (hm) from the imaginary vertex (Hm) of the main reflective element to the main plane (S-S) The ratio (hs/hm) is 0.39, the distance (hp) from the imaginary vertex (Hm) of the main reflecting element to the sub-plane (SH-SH) is 160m, and the ratio (hp/hm) is 0.89.

Using the same compression molding method as in Comparative Example 1, a retroreflective sheeting (invention sample 3) in which a plurality of composite cube-corner retroreflective elements made of polycarbonate were arranged in the most densely packed manner was produced.

Retroreflective sheetings (invention samples 1, 2 and 3) in which a plurality of composite cube corner retroreflective elements produced in Examples 1 to 3 were arranged in the most densely packed manner and triangular pyramids produced in Comparative Example 1 Table 1 shows the values of the retroreflective coefficients of the cube corner type retroreflective sheeting (comparative sample 1). Comparing the retroreflective coefficients of the retroreflective sheetings based on Embodiment 1 and Embodiment 2 of the present invention with the retroreflective coefficients of the triangular pyramid cube corner type retroreflective sheeting of Comparative Example 1 based on the conventional technology, in particularly large Under the observation angle, the retroreflection characteristic is better in the direction with a larger incident angle.

Table 1

Observation angle angle of incidence Invention Sample 1 Invention Sample 2 Invention Sample 3 Control sample 1 0.5° 5° 650 587 620 750 0.5° 10° 576 535 528 651 0.5° 20° 417 466 494 447 0.5° 30° 377 400 422 324 1.0° 5° 350 375 366 436 1.0° 10° 302 335 334 315 1.0° 20° 152 198 252 94 1.0° 30° 96 147 157 45

Industrial Applicability

The triangular pyramid cube corner retroreflective sheeting and retroreflective objects of the present invention can be used for markings such as road signs (general traffic signs and reflective signs), pavement markers (pavement maker), engineering signs, and vehicles such as automobiles and motorcycles. Number plates, reflective tapes attached to the body of trucks and trailers, safety equipment such as clothing, life-saving appliances, signs such as billboards, reflectors such as visible light, laser or infrared light reflective sensors, etc., can improve these products retroreflective performance.

Claims (34)

1. A retroreflector is characterized in that it comprises a composite cube corner retroreflective element, and its formation method is as follows: the V-shaped parallel groove groups passing through the 3 directions of the symmetrical cross section cross each other, and the 3 roughly at right angles are formed. At least two or more triangular-pyramid cube corner retroreflective elements called sub-reflective elements divided by intersecting reflective sides are most densely packed and arranged on a common sub-plane (SH-SH) One side protrudes, and through the V-shaped parallel groove groups arranged on the main plane (SS) and the cross-section is basically symmetrical in three directions, intersect each other, and the sub-reflector group is arranged in three roughly On a triangular-pyramidal cube corner retroreflective element called the main reflective element divided by reflective sides that intersect each other at right angles. 2. Retroreflector according to claim 1, characterized in that said secondary plane (SH-SH) is parallel to said main plane (S-S). 3. The retroreflective object according to claim 1 or 2, characterized in that the optical axis of the secondary reflective element and/or the primary reflective element is inclined. 4. The retroreflective object according to claim 3, characterized in that: the optical axis of the secondary reflective element and/or the main reflective element is inclined by 1-13°. 5 . The retroreflective object according to claim 3 , wherein the optical axis of the secondary reflective element and/or the main reflective element is inclined by 1.5° to 7°. 6. The retroreflective object as claimed in claim 1 or 2, characterized in that: the imaginary vertex (Hm) formed by the intersection of the extended planes of the three reflective side surfaces forming the main reflector element to the main plane (S— The distance hm of S) is 50 μm or more. 7. The retroreflective object as claimed in claim 6, characterized in that: the imaginary vertex (Hm) formed by the intersection of the extended planes of the three reflective side surfaces forming the main reflector element to the main plane (S—S) The distance hm is 80-300 μm. 8. The retroreflector as claimed in claim 6, characterized in that: the distance hs from the vertex (Hs) of the secondary reflective element to the secondary plane (SH-SH) is the same as the imaginary vertex (Hs) of the main reflective element ( The ratio hs/hm of the distance hm from Hm) to the main plane (S—S) is 0.1˜0.5. 9. The retroreflector as claimed in claim 8, characterized in that: the distance hs from the vertex (Hs) of the secondary reflective element to the secondary plane (SH-SH) is the same as the imaginary vertex (Hs) of the main reflective element ( The ratio hs/hm of the distance hm from Hm) to the main plane (S—S) is 0.1˜0.3. 10. The retroreflector as claimed in claim 6, characterized in that: the distance hp from the imaginary vertex (Hm) of the main reflective element to the secondary plane (SH-SH) is the same as the distance hp from the imaginary vertex (Hm) to The ratio hp/hm of the distance hm of the main plane (S—S) is 0.1˜0.9. 11. The retroreflector as claimed in claim 10, characterized in that: the distance hp from the imaginary vertex (Hm) of the main reflective element to the secondary plane (SH-SH) is the same as the distance hp from the imaginary vertex (Hm) to The ratio hp/hm of the distance hm of the main plane (S—S) is 0.3˜0.5. 12. The retroreflective object as claimed in claim 1 or 2, wherein at least one of the bottom edges in three directions forming the main reflective element and the bottom edges in the other three directions forming the secondary reflective element A set of directions whose bases are parallel. 13. The retroreflective object as claimed in claim 1 or 2, characterized in that: any of the bottom edges in three directions forming the main reflective element and the bottom edges in the other three directions forming the secondary reflective element The bases of a set of directions are all non-parallel. 14. The retroreflective object as claimed in claim 1 or 2, wherein one of the bases forming the three directions of the main reflective element and the bases forming the other three directions of the secondary reflective element The bases of the group directions form an angle of 30° to 60°. 15. The retroreflective object as claimed in claim 1 or 2, wherein one of the bases forming the three directions of the main reflective element and the bases forming the other three directions of the sub-reflecting element The bases of the group directions are at right angles. 16. The retroreflective object as claimed in claim 1 or 2, characterized in that: the track of at least one direction in the track of the bottom of the V-shaped groove forming the three directions of the sub-reflecting element is different from the track of forming the adjacent The tracks of the V-shaped grooves in the same direction as the sub-reflective elements contained in the main reflective element. 17. The retroreflective material according to claim 1 or 2, wherein the cross-sectional shape of at least one of the V-shaped grooves in three directions forming the sub-reflector is different from that of the adjacent main groove. The cross-sectional shape of the V-shaped grooves in the same direction of the sub-reflective element included in the reflective element. 18. A triangular pyramidal cube corner retroreflective sheeting, characterized in that it comprises a composite cube corner retroreflective element, and its formation method is as follows: the V-shaped parallel groove groups in 3 directions whose cross-section is basically symmetrical cross each other, At least two or more triangular pyramidal cube corner retroreflective elements called sub-reflective elements divided by three reflective side surfaces that cross each other at approximately right angles are arranged in the most densely packed manner toward a common sub-plane One side of (SH—SH) protrudes, and the group of V-shaped parallel grooves arranged on the main plane (SS) and having a substantially symmetrical cross-section in three directions intersect each other, and the group of sub-reflecting elements It is arranged on a triangular pyramid-shaped cube corner retroreflective element called a main reflective element divided by three reflective side surfaces crossing each other approximately at right angles. 19. The triangular pyramid cube corner retroreflective sheeting according to claim 18, wherein said secondary plane (SH-SH) is parallel to said main plane (S-S). 20. The triangular pyramid cube corner retroreflective sheeting according to claim 18 or 19, wherein the optical axis of the secondary reflective element and/or the primary reflective element is inclined. 21. The triangular pyramid cube corner retroreflective sheeting according to claim 20, wherein the optical axis of the secondary reflective element and/or the primary reflective element is inclined by 1-13°. 22. The triangular pyramid cube corner retroreflective sheeting according to claim 20, wherein the optical axis of the secondary reflective element and/or the primary reflective element is inclined by 1.5° to 7°. 23. The triangular pyramid cube corner retroreflective sheeting as claimed in claim 18 or 19, characterized in that: the imaginary vertex (Hm) formed by the crossing of the extended planes of the three reflective side surfaces forming the main reflective element reaches the The distance hm between the main planes (S—S) is 50 μm or more. 24. The triangular pyramid cube corner retroreflective sheeting as claimed in claim 23, characterized in that: the imaginary vertex (Hm) formed by the intersection of the extended planes of the three reflective side surfaces forming the main reflective element reaches to the main reflective element. The distance hm of the plane (S—S) is 80-300 μm. 25. The triangular pyramid cube corner retroreflective sheeting as claimed in claim 23, wherein the distance hs from the apex (Hs) of the secondary reflective element to the secondary plane (SH-SH) is the same as that of the main The ratio hs/hm of the distance hm from the imaginary vertex (Hm) of the reflective element to the main plane (S—S) is 0.1˜0.5. 26. The triangular pyramid cube corner retroreflective sheeting as claimed in claim 25, wherein the distance hs from the apex (Hs) of the secondary reflective element to the secondary plane (SH-SH) is the same as that of the primary reflector. The ratio hs/hm of the distance hm from the imaginary vertex (Hm) of the reflective element to the main plane (S—S) is 0.1˜0.3. 27. The triangular pyramid cube corner retroreflective sheeting as claimed in claim 23, wherein the distance hp from the imaginary vertex (Hm) of the main reflective element to the secondary plane (SH-SH) is equal to the distance hp of the The ratio hp/hm of the distance hm from the imaginary vertex (Hm) to the main plane (S—S) is 0.1˜0.9. 28. The triangular pyramid cube corner retroreflective sheeting as claimed in claim 27, wherein the distance hp from the imaginary vertex (Hm) of the main reflective element to the secondary plane (SH-SH) is equal to the distance hp of the The ratio hp/hm of the distance hm from the imaginary vertex (Hm) to the main plane (S—S) is 0.3˜0.5. 29. The triangular-pyramid cube corner retroreflective sheeting according to claim 18 or 19, wherein the bases of the three directions forming the main reflective element and the other three directions forming the secondary reflective element The bases of at least one set of orientations of the bases are parallel. 30. The triangular-pyramid cube corner retroreflective sheeting as claimed in claim 18 or 19, wherein the bases of the three directions forming the main reflective element and the other three directions forming the secondary reflective element The bases of any set of directions in the bases of are not parallel. 31. The triangular-pyramid cube corner retroreflective sheeting according to claim 18 or 19, wherein the bases of the three directions forming the main reflective element and the other three directions forming the secondary reflective element The bases of a group of directions in the bases form an angle of 30° to 60°. 32. The triangular-pyramid cube corner retroreflective sheeting according to claim 18 or 19, wherein the bases of the three directions forming the main reflective element and the other three directions forming the secondary reflective element The bases of a set of directions in the bases of are at right angles. 33. The triangular-pyramid cube corner retroreflective sheeting according to claim 18 or 19, wherein at least one of the tracks of the bottom of the V-shaped groove in three directions forming the sub-reflective element is The track is different from the track of V-shaped grooves in the same direction that form the sub-reflective elements included in the adjacent main reflective elements. 34. The triangular pyramid cube corner retroreflective sheeting according to claim 18 or 19, wherein the cross-sectional shape of at least one of the V-shaped grooves in three directions forming the sub-reflector element is It is different from the cross-sectional shape of the V-shaped grooves in the same direction that form the sub-reflective elements included in the adjacent main reflective elements.

Images